This invention relates to a process for the production of polymers of vinyl chloride which can be turned into a paste which process comprises polymerization in the presence of water-soluble catalysts and carboxylic acid salts as emulsifiers.
It has been known to produce polymers of vinyl chloride suitable for paste preparation in the presence of alkali salts of fatty acids as the emulsifiers, wherein the polymerization is conducted in an alkaline medium. Since the alkali metal salts of fatty acids have pH values of at least 9.5 in an aqueous medium they are thus fully effective as emulsifiers only at such pH values.
Polymers are obtained by the polymerization in the presence of alkali salts of fatty acids as emulsifiers which have a considerably higher thermal stability as compared to similar polymers obtained by the polymerization in the presence of alkyl sulfates, alkyl and alkylaryl sulfonates and other conventional emulsifiers. The polymers produced with alkali salts of fatty acids result, however, in pastes of unsatisfactorily high viscosities when used as plastisol material. Accordingly, there exists a need for obtaining vinyl chloride polymers combining good thermal stability with lower plastisol viscosity.